1// Copyright 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "content/browser/renderer_host/input/timeout_monitor.h"
6
7using base::Time;
8using base::TimeDelta;
9
10namespace content {
11
12TimeoutMonitor::TimeoutMonitor(const TimeoutHandler& timeout_handler)
13    : timeout_handler_(timeout_handler) {
14  DCHECK(!timeout_handler_.is_null());
15}
16
17TimeoutMonitor::~TimeoutMonitor() {}
18
19void TimeoutMonitor::Start(TimeDelta delay) {
20  // Set time_when_considered_timed_out_ if it's null. Also, update
21  // time_when_considered_timed_out_ if the caller's request is sooner than the
22  // existing one. This will have the side effect that the existing timeout will
23  // be forgotten.
24  Time requested_end_time = Time::Now() + delay;
25  if (time_when_considered_timed_out_.is_null() ||
26      time_when_considered_timed_out_ > requested_end_time)
27    time_when_considered_timed_out_ = requested_end_time;
28
29  // If we already have a timer with the same or shorter duration, then we can
30  // wait for it to finish.
31  if (timeout_timer_.IsRunning() && timeout_timer_.GetCurrentDelay() <= delay) {
32    // If time_when_considered_timed_out_ was null, this timer may fire early.
33    // CheckTimedOut handles that that by calling Start with the remaining time.
34    // If time_when_considered_timed_out_ was non-null, it means we still
35    // haven't been stopped, so we leave time_when_considered_timed_out_ as is.
36    return;
37  }
38
39  // Either the timer is not yet running, or we need to adjust the timer to
40  // fire sooner.
41  time_when_considered_timed_out_ = requested_end_time;
42  timeout_timer_.Stop();
43  timeout_timer_.Start(FROM_HERE, delay, this, &TimeoutMonitor::CheckTimedOut);
44}
45
46void TimeoutMonitor::Restart(TimeDelta delay) {
47  // Setting to null will cause StartTimeoutMonitor to restart the timer.
48  time_when_considered_timed_out_ = Time();
49  Start(delay);
50}
51
52void TimeoutMonitor::Stop() {
53  // We do not bother to stop the timeout_timer_ here in case it will be
54  // started again shortly, which happens to be the common use case.
55  time_when_considered_timed_out_ = Time();
56}
57
58void TimeoutMonitor::CheckTimedOut() {
59  // If we received a call to |Stop()|.
60  if (time_when_considered_timed_out_.is_null())
61    return;
62
63  // If we have not waited long enough, then wait some more.
64  Time now = Time::Now();
65  if (now < time_when_considered_timed_out_) {
66    Start(time_when_considered_timed_out_ - now);
67    return;
68  }
69
70  timeout_handler_.Run();
71}
72
73bool TimeoutMonitor::IsRunning() const {
74  return timeout_timer_.IsRunning() &&
75         !time_when_considered_timed_out_.is_null();
76}
77
78}  // namespace content
79